* [PATCH 1/4] block: move bvec iterator into include/linux/bvec_iter.h
2016-03-08 11:29 block & iov_iter: use bvec iterator to implement iterate_bvec() Ming Lei
@ 2016-03-08 11:29 ` Ming Lei
2016-03-08 11:29 ` [PATCH 2/4] block: make 'struct bvec_iter' not depend on CONFIG_BLOCK Ming Lei
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Ming Lei @ 2016-03-08 11:29 UTC (permalink / raw)
To: Jens Axboe, linux-kernel
Cc: linux-block, Christoph Hellwig, Al Viro, Anton Altaparmakov, Ming Lei
bvec iterator helpers should be used to implement
iterate_bvec():lib/iov_iter.c too, and this patch moves
them into the new header, so that we can keep bvec iterator
header out of CONFIG_BLOCK. Then we can avoid to reinvent
the wheel in iterate_bvec().
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
include/linux/bio.h | 55 +--------------------------------
include/linux/bvec_iter.h | 78 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 79 insertions(+), 54 deletions(-)
create mode 100644 include/linux/bvec_iter.h
diff --git a/include/linux/bio.h b/include/linux/bio.h
index cb68888..1e7248f 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -31,6 +31,7 @@
/* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
#include <linux/blk_types.h>
+#include <linux/bvec_iter.h>
#define BIO_DEBUG
@@ -40,10 +41,6 @@
#define BIO_BUG_ON
#endif
-#define BIO_MAX_PAGES 256
-#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
-#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
-
/*
* upper 16 bits of bi_rw define the io priority of this bio
*/
@@ -57,29 +54,6 @@
(bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
} while (0)
-/*
- * various member access, note that bio_data should of course not be used
- * on highmem page vectors
- */
-#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
-
-#define bvec_iter_page(bvec, iter) \
- (__bvec_iter_bvec((bvec), (iter))->bv_page)
-
-#define bvec_iter_len(bvec, iter) \
- min((iter).bi_size, \
- __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
-
-#define bvec_iter_offset(bvec, iter) \
- (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
-
-#define bvec_iter_bvec(bvec, iter) \
-((struct bio_vec) { \
- .bv_page = bvec_iter_page((bvec), (iter)), \
- .bv_len = bvec_iter_len((bvec), (iter)), \
- .bv_offset = bvec_iter_offset((bvec), (iter)), \
-})
-
#define bio_iter_iovec(bio, iter) \
bvec_iter_bvec((bio)->bi_io_vec, (iter))
@@ -193,33 +167,6 @@ static inline void *bio_data(struct bio *bio)
#define bio_for_each_segment_all(bvl, bio, i) \
for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
-static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
- unsigned bytes)
-{
- WARN_ONCE(bytes > iter->bi_size,
- "Attempted to advance past end of bvec iter\n");
-
- while (bytes) {
- unsigned len = min(bytes, bvec_iter_len(bv, *iter));
-
- bytes -= len;
- iter->bi_size -= len;
- iter->bi_bvec_done += len;
-
- if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
- iter->bi_bvec_done = 0;
- iter->bi_idx++;
- }
- }
-}
-
-#define for_each_bvec(bvl, bio_vec, iter, start) \
- for (iter = (start); \
- (iter).bi_size && \
- ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
- bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
-
-
static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
unsigned bytes)
{
diff --git a/include/linux/bvec_iter.h b/include/linux/bvec_iter.h
new file mode 100644
index 0000000..07c1ffc
--- /dev/null
+++ b/include/linux/bvec_iter.h
@@ -0,0 +1,78 @@
+/*
+ * bvec iterator
+ *
+ * Copyright (C) 2016 Ming Lei <ming.lei@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public Licens
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
+ */
+#ifndef __LINUX_BVEC_ITER_H
+#define __LINUX_BVEC_ITER_H
+
+#include <linux/blk_types.h>
+
+#define BIO_MAX_PAGES 256
+#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
+#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
+
+/*
+ * various member access, note that bio_data should of course not be used
+ * on highmem page vectors
+ */
+#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
+
+#define bvec_iter_page(bvec, iter) \
+ (__bvec_iter_bvec((bvec), (iter))->bv_page)
+
+#define bvec_iter_len(bvec, iter) \
+ min((iter).bi_size, \
+ __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
+
+#define bvec_iter_offset(bvec, iter) \
+ (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
+
+#define bvec_iter_bvec(bvec, iter) \
+((struct bio_vec) { \
+ .bv_page = bvec_iter_page((bvec), (iter)), \
+ .bv_len = bvec_iter_len((bvec), (iter)), \
+ .bv_offset = bvec_iter_offset((bvec), (iter)), \
+})
+
+static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
+ unsigned bytes)
+{
+ WARN_ONCE(bytes > iter->bi_size,
+ "Attempted to advance past end of bvec iter\n");
+
+ while (bytes) {
+ unsigned len = min(bytes, bvec_iter_len(bv, *iter));
+
+ bytes -= len;
+ iter->bi_size -= len;
+ iter->bi_bvec_done += len;
+
+ if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
+ iter->bi_bvec_done = 0;
+ iter->bi_idx++;
+ }
+ }
+}
+
+#define for_each_bvec(bvl, bio_vec, iter, start) \
+ for (iter = (start); \
+ (iter).bi_size && \
+ ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
+ bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
+
+#endif /* __LINUX_BVEC_ITER_H */
--
1.9.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 4/4] iov_iter: use bvec iterator to implement iterate_bvec()
2016-03-08 11:29 block & iov_iter: use bvec iterator to implement iterate_bvec() Ming Lei
` (2 preceding siblings ...)
2016-03-08 11:29 ` [PATCH 3/4] block: mark 1st parameter of bvec_iter_advance as const Ming Lei
@ 2016-03-08 11:29 ` Ming Lei
3 siblings, 0 replies; 5+ messages in thread
From: Ming Lei @ 2016-03-08 11:29 UTC (permalink / raw)
To: Jens Axboe, linux-kernel
Cc: linux-block, Christoph Hellwig, Al Viro, Anton Altaparmakov, Ming Lei
bvec has provided one iterator already, so not necessary
to invent a new wheel for this job.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
lib/iov_iter.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 5fecddc..5e1b224 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -3,6 +3,7 @@
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#include <linux/bvec_iter.h>
#include <net/checksum.h>
#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
@@ -57,35 +58,25 @@
}
#define iterate_bvec(i, n, __v, __p, skip, STEP) { \
- size_t wanted = n; \
+ struct bvec_iter __bi, __start; \
+ __start.bi_size = n; \
+ __start.bi_bvec_done = skip; \
+ __start.bi_idx = 0; \
__p = i->bvec; \
- __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
- if (likely(__v.bv_len)) { \
- __v.bv_page = __p->bv_page; \
- __v.bv_offset = __p->bv_offset + skip; \
+ for_each_bvec(__v, __p, __bi, __start) { \
(void)(STEP); \
- skip += __v.bv_len; \
- n -= __v.bv_len; \
} \
- while (unlikely(n)) { \
- __p++; \
- __v.bv_len = min_t(size_t, n, __p->bv_len); \
- if (unlikely(!__v.bv_len)) \
- continue; \
- __v.bv_page = __p->bv_page; \
- __v.bv_offset = __p->bv_offset; \
- (void)(STEP); \
+ if (!__bi.bi_idx) \
+ skip += __v.bv_len; \
+ else \
skip = __v.bv_len; \
- n -= __v.bv_len; \
- } \
- n = wanted; \
}
#define iterate_all_kinds(i, n, v, I, B, K) { \
size_t skip = i->iov_offset; \
if (unlikely(i->type & ITER_BVEC)) { \
const struct bio_vec *bvec; \
- struct bio_vec v; \
+ struct bio_vec v = { 0 }; \
iterate_bvec(i, n, v, bvec, skip, (B)) \
} else if (unlikely(i->type & ITER_KVEC)) { \
const struct kvec *kvec; \
@@ -102,7 +93,7 @@
size_t skip = i->iov_offset; \
if (unlikely(i->type & ITER_BVEC)) { \
const struct bio_vec *bvec; \
- struct bio_vec v; \
+ struct bio_vec v = { 0 }; \
iterate_bvec(i, n, v, bvec, skip, (B)) \
if (skip == bvec->bv_len) { \
bvec++; \
--
1.9.1
^ permalink raw reply [flat|nested] 5+ messages in thread